In a turbine installation which has a gas turbine acting as a generator for hot gas to power a free turbine the turbine intermediate case is located downstream of the gas generator turbine stages and between these stages and the free or power turbine. This support case is subject to severe thermal gradients and it has been found desirable to provide significant cooling for the outer ring or case forming a part of the outer engine structure.
In the copending application of Dennison Ser. No. 106,417 filed Dec. 21, 1979 is described a turbine intermediate bearing support structure in which there is a vent cavity adjacent the bearings in which air escaping past the seals is collected. This air has been vented to the atmosphere through the struts. Since this air is available and is relatively cool air, it is desirable that it be used for the purpose of cooling the outer case before escaping to the atmosphere.